Elevated circulating levels of certain amino acids (the building blocks of protein) are strongly associated with insulin resistance. This study will investigate the metabolism of these amino acids in individuals with normal glucose metabolism compared to overweight or obese pre-diabetic individuals. The purpose of this study is to determine how elevated levels of the branched-chain amino acids may contribute to the development of insulin resistance and ultimately diabetes. An additional purpose is to determine whether exercise or gastric bypass (GBP) surgery intervention can correct aberrations in branched-chain amino acid metabolism as insulin sensitivity improves. This information will be used to further our understanding of the development of insulin resistance and type 2 diabetes in at-risk populations and potentially improve clinical treatment of such conditions.

History of diabetes, heart disease or taking medication for those conditions

History of hypertension (high blood pressure) not controlled with medication

Pregnant or intending to become pregnant

Unwillingness to participate in study visits, submit to skeletal muscle biopsies and all other study testing or continuously participate in the exercise training intervention program for six months if in overweight PD group

Orthopedic limitations, musculoskeletal disease and/or injury

Allergic to xylocaine

Inability to give blood continuously through an intravenous catheter

Unwillingness to exercise at least three times per week at the Duke Center for Living during staff supervised times (PD only)

Exercise compliance less than 85% in any 6 week period (missing > 3 exercise sessions in a 6 week period)

Contacts and Locations

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study.
To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below.
For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT01786941